The present invention relates generally to devices for cleaning, disinfecting, and/or sterilizing a medical instrument in a rapid convenient manner. In a specific embodiment, the invention relates to a sterilizing device for instantaneously disinfecting a stethoscope.
Hospital-acquired infections, or “nosocomial” infections, are a common cause of mortality and morbidity in the hospital setting. Indeed, nosocomial infections are estimated to occur in 5% of all acute-care hospitalizations and upwards of 90,000 deaths each year can be attributed to hospital-acquired infections in the US alone.
Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacteria that is resistant to certain antibiotics. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin, and amoxicillin. Staph infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities (such as nursing homes and dialysis centers) who have weakened immune systems. MRSA infections that occur in otherwise healthy people who have not been recently (within the past year) hospitalized or had a medical procedure (such as dialysis, surgery, catheters) are known as community-associated (CA)-MRSA infections. These infections are usually skin infections, such as abscesses, boils, and other pus-filled lesions.
MRSA is particularly problematic for a number of reasons. As implied by the name, it is resistant to a number of the strongest antibiotics. Also importantly, MRSA is carried by people who do not exhibit symptoms making it a silent disease. Further, it can be easily transmitted through contact with infected skin or wound tissue. MRSA also causes particularly severe infections in hospitalized patients and persists indefinitely in the skin and noses of persons infected, leaving these people susceptible to subsequent infection.
Although MRSA is the prototypical microorganism responsible for hospital-acquired infection, other organisms are also commonly spread between hospitalized patients by healthcare providers. These include clostridium difficile, enterococcus species (in particular, vancomycin-resistant enterococcus or VRE), E. coli, pseudomonas aeruginosa, group A and group B streptococcus species, numerous virus species including hepatitis A and B viruses, and other infectious agents.
Despite the obvious societal benefits to reducing the occurrences of nosocomial infections, there are powerful economic incentives as well. For example, Medicare has recently announced that it will no longer reimburse hospitals for certain nosocomial infections. Consequently, a significant portion of the burden of treating such infections will shift to the hospitals, thus providing a further financial motivation to reduce occurrences.
Research has shown that hospital workers are a significant contributor in the transmission of infectious agents to hospitalized patients. For example, certain commonly-used medical instruments are not sanitized sufficiently. One particular instrument that is involved in virtually every patient visit is the stethoscope, but surprisingly, most stethoscopes are cleaned rarely if ever. Collected data has shown that 80% to 100% of stethoscopes used by hospital workers carry infectious agents, including MRSA.
In view of the risks presented by contaminated stethoscopes, certain strategies have been attempted to minimize the transmission of infectious agents, yet none have been satisfactory. One prior art method involves the use of disposable covers that can be placed over the head of the stethoscope. Although proper use can shield a contaminated stethoscope from a patient, the cover reduces the sensitivity of the instrument. Other prior art methods typically involve placing all or a portion of the stethoscope in a cabinet where it can be exposed to a germicidal agent. These methods often suffer from poor compliance due to the length of time and number of steps required to effect the sterilization. Yet another prior art device is a small container holding a sponge saturated with disinfectant. One disadvantage of at least some prior art devices is their portability, which means either they are easily misplaced or they will be located in different areas, reducing the chances their use will become a routine habit. Another disadvantage of at least some prior art devices is that they require two hands to operate (e.g. with a lid that must be unscrewed or otherwise opened) which reduces the ease of use and increases the amount of time required. Yet another disadvantage of at least some prior art devices is that they generally provide no indication of when the amount of disinfectant is exhausted such that they are no longer able to adequately sterilize the stethoscope, leading to a false sense of safety.